Air may be passed into a room through floor or ceiling ventilators or, less usually, through wall ventilators.
One particular problem with which the present invention is concerned is the placement and fixing of ventilators such as ceiling ventilators. Thus one type is known which makes use of spring-loaded catches connected to inner locations on such a ceiling ventilator. A suitably sized and shaped hole may be cut in the ceiling and a ventilator of this type inserted through the hole. The catches may then be tripped so that they grip the ceiling holding the ventilator in place. Such catches may not have sufficient strength to hold a heavy ventilator in position.
The object of the present invention is to overcome the problem outlined above and provide a ventilator which can be inserted, positioned and fastened from below the ceiling or outside the wall or above the floor.